This invention relates to a windshield wiper for wiping the glass of a windshield of an automotive vehicle.
A windshield wiper for wiping the glass of a windshield of an automotive vehicle is disposed in front of the driver and subjected to the pressure of wind during reciprocatory movement on its blade when the vehicle travels at high speed. The blade tends to be blown by the wind pressure and brought out of contact with the surface of the windshield, particularly during its return stroke. Thus windshield wipers of the prior art have suffered the disadvantage that the surface of the windshield is not cleaned satisfactorily and the field of view of the driver is blurred, so that the visibility of the driver is obstructed.
To obviate this disadvantage, various proposals have hitherto been made to void the wiper blade being brought out of contact with the windshield. In one proposal, the force of a spring of the windshield wiper device is increased to press the wiper blade against the surface of the windshield with a force greater than conventional devices. In this case, frictional resistance between the wiper blade and the surface of the windshield increases and makes it necessary to use a powerful motor (large size and high power consumption) for driving the wiper. In addition, there is the disadvantage that when the automotive vehicle at low speed or remains stationary, the wiper blade does not operate effectively to wipe the surface of the windshield.
In another proposal, a vane-shaped member of a large size is attached to the support metal member or support arm. The wind pressure causes the vane-shaped member to produce a force (counter-lift) for pressing the wiper blade against the surface of the windshield. Therefore, the counter-lift force and the force tending to cause the wiper blade to be brought out of contact with the windshield will cancel each other.
When the vane-shaped member is used as proposed, a force tending to press the wiper blade against the surface of the windshield would be generated in principle with an increase in the velocity of the wind blowing against the vane-shaped member. By the way, the direction and the velocity of the wind striking the windshield are not uniform. When the elevation angle of the vane-shaped member suits the wind, the vane-shaped member could achieve the desired effect. However, when the wind is blowing in a direction which is not favorable for the elevation angle, the wiper blade would be brought out of contact with the windshield or would be chattered. With the result, the windshield would not be cleaned satisfactorily. An additional disadvantage is that the field of view of the driver would be narrowed and safe driving of the automotive vehicle would be interfered.